农田地表径流中溶质流失规律研究

本文根据地表径流中溶质流失的流动特征和物理规律,基于矢量合成概念,建立了二层解析模型,描述从降雨开始径流使水溶质在地表的流失过程.该模型考虑了土壤中溶质的入渗和扩散作用,通过非完全混合参数得到表面流失和入渗的合成.在溶质质量守恒和水量平衡的基础上,将土壤混合层和积水径流混合层作为研究对象,得到解析解.根据前人的实验结果,利用本文所提出的模型,分析了无积水和有积水时地表径流水中的溶质浓度,模拟结果基本能够反映径流溶质浓度变化特征,为农业面源污染的分析提供有意义的参考.

Dissolved chemical loss in surface runoff of farm land

A simple two layer analytical model was developed to describe the process of dissolved chemical loss in surface runoff from the beginning of runoff occurrence. In the model both the filtration and diffusion processes were considered as vectors in vertical direction and synthesized by incomplete mixing parameters. Based on chemical conservation laws and water balance equations, this model can study the chemical loss in whole mixing layer including the ponding runoff and soil mixing layer. An analytical solution was obtained. By using the parameters given by other authors, the model was applied to analyze the soluble chemical concentration in runoff under the condition of absent ponding water or having ponding water. The result obtained by the proposed model reasonably reflected the variation characteristics of the chemical concentration in runoff, which will provide reference for agricultural non point pollution.